Aims: This research investigates how mothers experience parent-infant psychotherapy (PIP). The study uses a collaborative exploration of mothers' lived experience and the meaning they attach to it. The intention is to develop insights into mothers' variety of experience of PIP and how their subjectivity impacts their perception of the therapeutic process. Using their in-depth descriptions, this study develops an understanding of the themes inherent in the experience of women in motherhood. Design: This research uses phenomenology, hermeneutics and idiography as a philsosophical base, and applies interpretative phenomenological analysis methodology, drawing upon Jonathan Smith's concept of experiential qualitative research in psychology (2009). This approach was chosen in order to develop an understanding of the insider perspective by engaging directly with mothers' own descriptive accounts of PIP. Method: Seven women, aged between 27 and 43 years old, voluntarily participated in this study. The volunteers were recruited from among participants of a group of PIP course delivered by a National Health Service (NHS) clinic. In-depth semi-structured interviews were conducted to develop an understanding of participants' lived experience and their meaning-making processes. Findings: Three master themes emerged from across the participants' accounts: (1) from a negative to a positive experience of motherhood, (2) PIP as a nurturing experience, (3) PIP as a humanising experience, and (4) PIP as a transformative experience. The findings highlight the significant change in mothers' perception of motherhood (their state of being a mother) - from a sense of inability, detachment, isolation and depression to feeling different, competent, maternal and relationally attached - which they attribute to their experience of PIP. It gave them a different vantage point from which to feel, behave, think, understand and engage with themselves and the world. Conclusion: PIP is valued by mothers as a potentially powerful therapeutic intervention and vehicle for change for themselves, their children and the generations to come. The mothers, psychotherapists, the group setting are all essential to the success of the therapeutic encounter. Mothers should be given the opportunity to access such treatment at this precious and formative time in their and their children's lives.